BY DR QAZI IMTIAZ RASOOL

1. Define respiration and identify different levels of respiratory process and the contributing parts of the body. 2. Describe the physiological anatomy of the respiratory system (= List the parts of conductive zone and components of respiratory zone). 3. Discuss its functions of the conducting zone (= respiratory passages). What is This Lecture About?

Adam’s ventilatory apparatus—a rib—gave life to Eve 4 th century B.C. writings attributed to Hippocrates depict the cooling of heart as the primary purpose of breathing Higher animals

Introduction Respiratio (French) Re-spiro—to exhale, to breathe Is a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances. Digested FoodEnergy + CO 2 o2o2

Respiration can be classified as: Aerobic, AnaerobicExternal, Internal Direct, Indirect Voluntary, Involuntary Collateral ventilation,Cellular respiration

HEART TISSUE CELL O 2 + FOOD CO 2 + H 2 O + ATP LUNGS ATMOSPHERE PULMONARY CIRULATION SYSTEMIC CIRCULATION

Stages of the Breath: 1. Inhaling Oxygen (Air) INTO the Body: Inhalation (or inspiration) is active breathing phase. 2. Gas Exchange in the Lungs: 3. Exhaling Carbon

Respiratory apparatus includes 1.Respiratory Tract2.Thoracic cavity & Muscles of Respiration (PUMP)3. With their Nervous control

Clinically 2 parts Upper respiratory tract Lower respiratory tract

Upper Respiratory Tract Nose Sinuses Glottis Pharynx Larynx Structures from nose to vocal cords To “Process” the inspired air:-

Lower Respiratory Tract Trachea Bronchi Bronchioles Alveolar ducts Alveoli

Nose 3. Contains Olfactory Epithelium that receives smell n sensation 6. Filters particles > 10 µm 4. Contains Igs & Interferons and mucus production for protection ( bacteria, dust, pollen, etc.). 5. Offers 50% resistance to airflow in the RS 1. Air conditioning (warming, cooling), 2. Resonating chamber for speech

Paranasal Sinuses Around the nasal cavity4 sinuses, Maxillary, frontal, sphenoid, ethmoid 3 functions 1.Offer resonance to voice 2. Lighten the skull –→ upright posture becomes easier 3. Provide protection to brain during facial trauma

- is a tube 12 to 14 cm long Nasopharynxsituated behind nose posterior nares to soft palate Oropharynx situated behind mouth soft palate—hyoid bone level Laryngopharynx hyoid bone to esophagus Function— 1. Passageway for air and food. 2. Warming and humidifying. 3. Taste.. 4. Hearing. 5. Protection. 6. Speech.

9 cartilages connected by membranes and ligaments Thyroid cartilage with laryngeal prominence (Adam’s apple) anteriorly Consists of Epiglottis, Arytenoids, Vocal cords Epiglottis n arytenoids cover the vocal cords during deglutition n prevent aspiration of food during respiration Vocal cords are for production n modification of voice Function : 1.Produces vocalizations (speech) 2.Provides an open airway (breathing) 3.Switching mechanism to route air and food into proper channels Closed during swallowing Open during breathing

1.Trachea R+L main bronchi 2.lobar bronchi 3.segmental bronchi 4.bronchioles 5. TERMINAL BRONCHIOLES 1.RESPIRATORY BRONCHIOLE s 2.alveolar ducts 3.atria 4. alveolar sacs conducting zone generations 1-16 respiratory zone primary lobule / or acinus generations 17-23

As the generation number ↑s : 1. Airways become smaller, shorter and narrower 2. The amount of cartilage in the wall ↓s 3. The no. of submucosal glands ↓s 4. The no. of mucous-secreting cells ↓s 5. The no. of cilia ↓s 6. The total cross-sectional area ↑s (2.5 cm 2 in the trachea thru 180 cm 2 in terminal bronchioles to 11,800 cm 2 in the alveoli; about are in contact with capillaries7000cm 2 )

1. Some amount of cartilage present up to 10 th generation(prevent collapse of airways ) and absent in bronchioles 2. Bronchioles Suspended by elastic tissue of lung parenchyma 3. First 16 airway generations lack alveoli and form the anatomical dead space. 4. Portion of the lung supplied by primary respiratory bronchiole is acinus

1. Support and patency They distribute air evenly to deeper parts of lungs 2. They serve as part of Non-specific Defense System of body by removing dust, bacteria and harmful gases from resp. tract 3. Mucociliary escalator Mucous lines the inner wall of airways like carpet & traps small foreign particles 4. Provides a low-resistance pathway for air flow; resistance is physiologically regulated by changes in contraction of airway smooth muscle and by physical forces acting upon the airways. 5. Warming, humidifying and filtering of air. 6. Phonates (vocal cords). 7. Cough reflex

site of gas exchange 1. Last 7 generations of airways generation respiratory bronchioles generation alveolar ducts alveolar sac 5. This region is only approximately 5 mm long 6. Alveoli start budding off from 17 gen (~ 300 million) 7. All airways of a single terminal bronchiole (resp. bronchioles, alveolar ducts ‘n’ sacs) with associated blood and lymphatic vessels constitute a primary lobule (terminal resp. unit) 8. Resp zone supplied by pulmonary circulation 9. Extensive capillary network occupies 80% of alveolar surface area 10. Perialveolar capillaries proximate blood to alveolar air—easy diffusion of gases site of gas exchange 1. Last 7 generations of airways generation respiratory bronchioles generation alveolar ducts alveolar sac 5. This region is only approximately 5 mm long 6. Alveoli start budding off from 17 gen (~ 300 million) 7. All airways of a single terminal bronchiole (resp. bronchioles, alveolar ducts ‘n’ sacs) with associated blood and lymphatic vessels constitute a primary lobule (terminal resp. unit) 8. Resp zone supplied by pulmonary circulation 9. Extensive capillary network occupies 80% of alveolar surface area 10. Perialveolar capillaries proximate blood to alveolar air—easy diffusion of gases

µm diameter 2. Total alveolar area in contact with capillaries in both lungs approx. 70m 2 3. Type I -flat cells, primary lining cells of alveoli, covering 95% alveolar epithelial surface area 4. Type II (granular pneumocytes)— → thicker, contain numerous lamellar inclusion bodies → secrete surfactant → imp. in alveolar repair → make up 5% surface area → represent 60% epithelial cells in alveoli µm diameter 2. Total alveolar area in contact with capillaries in both lungs approx. 70m 2 3. Type I -flat cells, primary lining cells of alveoli, covering 95% alveolar epithelial surface area 4. Type II (granular pneumocytes)— → thicker, contain numerous lamellar inclusion bodies → secrete surfactant → imp. in alveolar repair → make up 5% surface area → represent 60% epithelial cells in alveoli

1. Pulmonary alveolar macrophages 2. Lymphocytes 3. Plasma cells 4. Mast cells containing 5. APUD cells heparin, histamine, lipids & proteases that participate in allergic

1.External respiration 2. Defence against microbes 1.lymphocytes 2. plasma cells, 3. macrophages 3. Warming and humidifying

a) Left ventricular reservoir= 0.5 L of blood b) Filtering small emboli = Clots, fat or air bubbles: c) Biochemical functions= → chemical substances removed PGE 2, PGF 2a, leukotriens, serotonin and bradykinin; → 250 volatile substances removed i.e methane(from intestines), alcohol, acetone, etc. d) Olfactory function e) Coughing and sneezing f) Processing of inhaled air –filtration of toxic substances & organisms g) Endocrine function—converts ANG 1 to ANG 2 h) Defense functions=→ alveolar & interstitial macrophages remove particles < 2µm → IgA, collectins (including Surfactant A and D), → defensins and proteases, reactive oxygen PGE2 → chemokines and cytokines secrete (immune cells) i) Metabolic functions— synthesis of surfactant lyse clot (local fibrinolytic system) synthesis of local hormones like histamine, kallikrein, PGs j) Temperature control=panting

1. Lungs are in a space with a volume of approximately 4 L, and surface area for gas exchange is the size of a tennis court (∼70-85 m 2 ). 2. Adults, the lung weighs = 1 kg, with lung tissue accounting for 60% 3. Volume of the nose in an adult is 20 mL 4. Lymphatic channels are more abundant in the lungs than in any other organ 5. Circulation to the lung is unique in its dual circulation and ability to accommodate large volumes of blood at low pressure.